Expandable tip medical devices and methods

ABSTRACT

Guidewires and methods of use of guidewires having improved atraumatic tips that can distribute force to lessen trauma as well as anchor the guidewire to facilitate improved catheter exchange.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a divisional of U.S. patent application Ser.No. 15/040,119, filed Feb. 10, 2016, which claims the benefit ofpriority to U.S. Provisional Application No. 62/115,006, filed Feb. 11,2015, the contents of each of which are incorporated by reference hereinin their entireties.

FIELD

The disclosure provided herein relates to guidewires and other medicaldevices having improved atraumatic tips that can distribute force tolessen trauma as well as anchor the guidewire or device to facilitateimproved catheter insertion, removal and/or exchange.

BACKGROUND

Exchange length guidewires are often used during procedures ininterventional radiology, including interventional cardiology,interventional neuroradiology, and interventional peripheral radiology.

The exchange length guidewires are used to facilitate exchanging ofdevices such as catheters or microcatheters, over a guidewire where,e.g., the physician removes a first microcatheter from a guidewire thatis positioned at a site of interest and then advances a secondmicrocatheter over the guidewire to that site in the vasculature.

For example, a physician may replace the original microcatheter withanother catheter or a separate device having different properties orbetter suited for the intended procedure (e.g. better condition, morenavigable, better supporting, etc.). For example, a first microcathetercan be used with properties that allow for accessing or navigation tothe target site but a second microcatheter might be better suited tosupport or provide access for medical devices to the target site.Regardless, a physician performs a procedure for catheter exchange byplacing a first microcatheter at a desired location within thevasculature often using a standard guidewire. Next, the physicianremoves the standard guidewire from the first microcatheter whileleaving the first microcatheter at the site. The physician then insertsan exchange length guidewire (usually 280 cm to 300 cm in length)through the first microcatheter and positions a distal end of theexchange length guidewire at the intended site.

Once this exchange length guidewire is loaded into the microcatheter andpositioned in the anatomy, the first microcatheter can be removed andreplaced with a different microcatheter. The extra length of theexchange length guidewire enables the removal and replacement of themicrocatheter (referred to as an exchange procedure) without loss ofdirect access to the proximal end of the guidewire by the physician.

The physician must perform an exchange procedure with caution becauseexcessive movement of the tip of the exchange guidewire can causeirritation or even damage to the vessel. This is especially true fordelicate vasculature such as the neurovasculature. In some extremecases, excessive movement of the guidewire tip can perforate the vesselwall during the exchange procedure. Because of this, the exchangeprocedure typically takes place very slowly, where the physician removesthe first microcatheter in incremental movements by holding the proximalend of the exchange guidewire and while simultaneously trying to preventexcessive movement of the exchange guidewire. Once the physician removesthe first microcatheter, the physician advances a second microcatheterover the exchange guidewire and navigates the second microcatheterdistally again while holding the proximal end of the guidewire andpreventing as much motion as possible.

However, even with near immobilization of the proximal end of theguidewire, the distal end of the guidewire may still move more thandesired. This unwanted motion can be the result of imprecise holding ofthe guidewire, or the result of the advancement of the microcatheterwhich causes undesired motion of the guidewire, or the result of patientmovement during the breathing cycle, etc.

In any case, it is this unintended motion of the distal end of theguidewire that can cause the vessel irritation, spasm, dissection,and/or perforation. Physicians often curve the distal end of theguidewire to attempt to make it less traumatic; this practice may helpsomewhat but it may not lower the risk of vessel damage sufficiently.For example, as shown in FIG. 1, a microcatheter 12 advances along aguidewire 14 having a “J-tip” or “J-curve” 16. However, the J-curve 16does not distribute the force sufficiently and can cause trauma to thewalls of the vessel 10 along the portion of the guidewire 14 that isshaped into the curve 16.

SUMMARY

The illustrations and variations described herein are meant to provideexamples of the methods and devices of the subject technology. It iscontemplated that combinations of aspects of specific embodiments orcombinations of the specific embodiments themselves are within the scopeof this disclosure.

The examples discussed herein show the devices and methods of thepresent disclosure in a form that is suitable to assist in catheterexchange procedures. However, the guidewires described herein can beused for any vascular or non-vascular access procedure in which aguidewire is used to assist in accessing a target site within theanatomy.

It should also be noted that although this disclosure discusses exchangelength guidewires, the improved guidewires of this disclosure can bemanufactured in any length, e.g., a shorter length for a standard guidewire length. In this case, the physician can remove the originalprocedural guidewire and replace it with the expandable tipped guidewiredisclosed herein. This could be desired if the physician does not planto replace or exchange a microcatheter but nonetheless prefers a wirethat is more atraumatic and/or offers anchoring for enhanced navigationor manipulation of the catheter.

In one example, an improved guidewire comprises a guidewire body havinga distal end; a plurality of elements extending along a distal portionof the guidewire body and diverging from the distal end of the guidewirebody to form a compliant structure having an expanded profile that isgreater than a radial dimension of the distal end of the guidewire bodyand being resiliently deformable to a reduced profile, where in theexpanded profile the compliant structure optionally provides a uniformradial force in an outward circumferential direction from an axis of theguidewire body; and where the plurality of elements return to the distalportion of the guidewire body and extend along a distal portion of theguide wire body.

Variations of the guidewires can include a guidewire body comprising asolid core member and where the plurality of elements are affixed to thesolid core member along the portion of the proximal end of the guidewire body.

The compliant structure, and/or the anchoring portions of the devicescan optionally be made to be fluid permeable to allow fluid flowtherethrough.

Variations of the devices include compliant structures where theplurality of strut member comprise at least a first strut and a secondstrut, where a cross sectional area of the first strut is different thana cross sectional area of the second strut. The struts and/or elementsforming the compliant structure can be interwoven or braided to form thecompliant structure. In some variations, the struts/element can beinterwoven and braided in various parts of the compliant structure.

In some variations of the device, the plurality of elements on thedistal portion of the guidewire body increase a column strength of thedistal portion of the guidewire body.

In another variation, the improved guidewire comprises a guidewire bodyextending between a proximal portion and a distal portion, the guidewirebody comprising an elongated shape and configured to navigate thetortuous anatomy; a plurality of strut members arranged to form a framemember having a diameter greater than a cross sectional diameter of thedistal portion of the guidewire body; where the plurality of elements inthe frame member can move relative to each other causing the framemember to be compliant and optionally provide a uniform radial force inan outward circumferential direction from the guidewire body whenreleased from a constraining force; and the plurality of elementsconverging from a proximal end of the frame member to extend along thedistal portion of the guidewire body, where the plurality of elementsare continuous.

The present disclosure also includes improved methods of performing acatheter exchange procedure. One example includes inserting a catheterinto a blood vessel having a flow of blood therethrough and positioninga first catheter into the blood vessel; advancing a guidewire into thefirst catheter, where the guidewire comprises a guidewire body extendingbetween a proximal end and a distal end, and a compliant structurelocated at the distal end of the guidewire body, where a first portionof the compliant structure is collapsible to permit advancement throughthe first catheter and self-expandable upon deployment from the firstcatheter, where a proximal portion of the compliant structure iscontinuous and extends along a proximal portion of the guidewire;deploying the compliant structure into the blood vessel from a distalend of the first catheter such that the compliant structure optionallyexpands in a uniform radial direction from the guidewire body againstthe blood vessel thereby permitting a distribution of force against theblood vessel allowing for the compliant structure to temporarily anchorthe guidewire within the blood vessel; withdrawing the first catheterout of the blood vessel while maintaining the guidewire within the bloodvessel; and advancing a second catheter over the guidewire.

In another variation, the guidewire devices described herein arefabricated in a manner that eliminates or reduces the number of jointsand/or connection points in the device. Doing so allows the device tohave a compact and smooth configuration making it easier for deliverythrough a microcatheter; and leads to a safer device less prone tobreaking.

The subject technology is illustrated, for example, according to variousaspects described below. Various examples of aspects of the subjecttechnology are described as numbered clauses (1, 2, 3, etc.) forconvenience. These are provided as examples and do not limit the subjecttechnology. It is noted that any of the dependent clauses may becombined in any combination, and placed into a respective independentclause, e.g., clause 1 or clause 5. The other clauses can be presentedin a similar manner.

Clause 1. A guidewire comprising:

-   -   a guidewire body having a distal end;    -   a plurality of elements having a proximal section extending        along a distal portion of the guidewire body, and a distal        section in which the plurality of elements diverge radially        outward from the distal end of the guidewire body to form a        compliant structure having an expanded profile that is greater        than a radial dimension of the distal end of the guidewire body        and being resiliently deformable to a reduced profile, where in        the expanded profile the compliant structure provides a radial        force in an outward circumferential direction from an axis of        the guidewire body.

Clause 2. The guidewire of Clause 1, where the guidewire body comprisesa core member and where the plurality of elements, in said proximalsection, are affixed to the core member along the distal end of theguidewire body.

Clause 3. The guidewire of Clause 2, where the plurality of elements, insaid proximal section, are not radially expandable away from the coremember.

Clause 4. The guidewire of Clause 1, where the compliant structurecomprises a shape selected from the group consisting of spherical,egg-shaped, football-shaped, elliptical, conical, cylindrical.

Clause 5. The guidewire of Clause 1, where the plurality of elementscomprises at least a first strut and a second strut, where a crosssectional area of the first strut is different than a cross sectionalarea of the second strut.

Clause 6. The guidewire of Clause 1, where the plurality of elementsforming the compliant structure are interwoven to form the compliantstructure.

Clause 7. The guidewire of Clause 1, where the plurality of elementsforming the compliant structure are braided to form the compliantstructure.

Clause 8. The guidewire of Clause 1, where at least one of the pluralityof elements forming the compliant structure is heat set.

Clause 9. The guidewire of Clause 1, where at least one of the pluralityof elements forming the compliant structure comprises a materialselected from the group consisting of a drawn filled tube, a nitinolwire, a shape memory alloy, a super-elastic alloy, a stainless steelmaterial, and a platinum material.

Clause 10. The guidewire of Clause 1, where the plurality of elements,in said proximal section, are bonded to the guidewire body.

Clause 11. The guidewire of Clause 1, where the plurality of elements onthe distal portion of the guidewire body increase a column strength ofthe distal portion of the guidewire body.

Clause 12. The guidewire of Clause 1, where the guidewire body comprisesa core member and where the plurality of elements, in said proximalsection, are affixed against the solid core member along the distal endof the guidewire body.

Clause 13. The guidewire of Clause 1, where the compliant structure ispermeable to allow fluid flow therethrough.

Clause 14. A guidewire for advancing through a body lumen in a tortuousanatomy, the guidewire comprising:

-   -   a guidewire body extending between a proximal portion and a        distal portion, the guidewire body comprising an elongated shape        and configured to navigate the tortuous anatomy;    -   a plurality of elements arranged to form a frame member having a        diameter greater than a cross sectional diameter of the distal        portion of the guidewire body;    -   where the plurality of elements in the frame member can move        relative to each other causing the frame member to be compliant        and provide a radial force in an outward circumferential        direction from the guidewire body when released from a        constraining force; and    -   the plurality of elements converging from a proximal region of        the frame member to extend proximally from the frame member        along the distal portion of the guidewire body, thereby forming        a proximal extension of the plurality of elements, where the        plurality of elements are continuous from the frame member into        the proximal extension along the distal portion of the guidewire        body.

Clause 15. The guidewire of Clause 14, where the guidewire bodycomprises a core member and where the plurality of elements are affixedto the core member along the proximal extension of the plurality ofelements.

Clause 16. The guidewire of Clause 15, where the plurality of elements,in said proximal extension, are not radially expandable away from thecore member.

Clause 17. The guidewire of Clause 14, where the frame member comprisesa shape selected from the group consisting of spherical, egg-shaped,football-shaped, elliptical, conical, cylindrical.

Clause 18. The guidewire of Clause 14, where the plurality of elementscomprises at least a first strut and a second strut, where a crosssectional area of the first strut is different than a cross sectionalarea of the second strut.

Clause 19. The guidewire of Clause 14, where the plurality of elementsforming the frame member are interwoven to form the frame member.

Clause 20. The guidewire of Clause 14, where the plurality of elementsforming the frame member are braided to form the frame member.

Clause 21. The guidewire of Clause 14, where the frame member ispermeable to allow fluid flow therethrough.

Clause 22. The guidewire of Clause 14, where at least one of theplurality of elements forming the frame member comprises a materialselected from the group consisting of a drawn filled tube, a nitinolwire, a shape memory alloy, a super-elastic alloy, a stainless steelmaterial, and a platinum material.

Clause 23. The guidewire of Clause 14, where the plurality of elements,in said proximal extension, are bonded to the guidewire body.

Clause 24. The guidewire of Clause 14, where the plurality of elementsin said proximal extension increase a column strength of a distalportion of the guidewire body.

Clause 25. The guidewire of Clause 1, where the guidewire body comprisesa core member and where the plurality of elements, in said proximalsection, are affixed against the solid core member along the distal endof the guidewire body.

Clause 26. A method of inserting a catheter into a blood vessel having aflow of blood therethrough, the method comprising:

-   -   positioning a first catheter into the blood vessel;    -   advancing a guidewire into the first catheter, where the        guidewire comprises a guidewire body extending between a        proximal end and a distal end, and a compliant structure located        at the distal end of the guidewire body, where a first portion        of the compliant structure is collapsible to permit advancement        through the first catheter and self-expandable upon deployment        from the first catheter, where a proximal portion of the        compliant structure is continuous and extends along a distal        portion of the guidewire;    -   deploying the compliant structure into the blood vessel from a        distal end of the first catheter such that the compliant        structure expands in a uniform radial direction from the        guidewire body against the blood vessel thereby permitting a        distribution of force against the blood vessel allowing for the        compliant structure to temporarily anchor the guidewire within        the blood vessel;    -   withdrawing the first catheter out of the blood vessel while        maintaining the guidewire within the blood vessel; and    -   advancing a second catheter over the guidewire.

BRIEF DESCRIPTION OF THE DRAWINGS

Each of the following figures diagrammatically illustrates aspects andvariation to better understand the invention. Variation of the inventionfrom the aspects shown in the figures is contemplated.

FIG. 1 illustrates a traditional J-tip guidewire being used with acatheter.

FIG. 2A illustrates an example of an improved guidewire having aguidewire body 102 and compliant member.

FIG. 2B illustrates a magnified view of a distal section of an improvedguidewire.

FIG. 3A illustrates a plurality of elements or struts that can formcompliant structure.

FIG. 3B represents an alternative of a compliant structure formed as adiscrete or separate structure, such as a discrete braid or laser cuttube or sheet.

FIG. 3C illustrates an expandable tip structure or compliant structurehaving a continuous or integral proximal section, shown apart from itslocation of attachment to a guidewire body.

FIGS. 4A and 4B show cross sectional view of an example of a variationof an element or strut comprising a plurality of wires or a DFTmaterial.

FIG. 5A illustrates one example of a guidewire deployed through amicrocatheter where the anchoring portion of the compliant memberprovides an atraumatic tip to the guidewire.

FIG. 5B illustrates one example of a guidewire deployed through amicrocatheter where the anchoring portion of the compliant memberprovides an atraumatic tip to the guidewire.

FIGS. 6A to 6E illustrate a number of profiles and shapes for the anchorportion of the compliant structure.

DETAILED DESCRIPTION

The ideas presented in this disclosure can be used in any corporeallumen or tubular organ/duct within the body, but as described above canreduce undesired complications when used within the vasculature,especially delicate vasculature such as the cerebral vasculature.However, unless specifically noted, variations of the device and methodare not limited to use in the cerebral vasculature. Instead, theinvention may have applicability in various any part of the body.Moreover, the invention may be used in various procedures where thebenefits of the method and/or device are desired.

FIG. 2A illustrates an example of an improved guidewire 100 having aguidewire body 102 and compliant member 104. The guidewire body 102 canbe constructed according to any number of conventional methods.Typically, the guidewire body 102 comprises a solid core member thatallows for tracking and advancement of the guidewire through tortuousanatomy. In certain variations, the guidewire body 102 can include alumen. The improved guidewire 100 also includes an expandable tipstructure or compliant structure 104. The compliant structure 104 isfabricated to be collapsible when positioned within a catheter thatwould apply a constraining force on the fully expanded profile of thecompliant structure 104. Upon removal of the constraining force, or whenadvanced from the distal end of the catheter, the compliant structure104 assumes an expanded profile as shown. The expanded profile isgreater than a cross sectional measurement or radial dimension of thedistal end of the guide wire body 102. Sizing of the compliant structure102 in this manner allows the compliant structure 104 to serve as atemporary anchor when placed within a lumen having a smaller or the samediameter as that of the compliant structure 104.

The compliant structure 104 can function as a soft tip that causessignificantly less trauma than a regular guidewire tip or the J-tip. Thecompliant tip or structure 104 expands radially away from an axis of theguidewire body. This radial expansion increases the contact surfacebetween the compliant structure 104 and the lumen wall to betterdistribute any forces applied by the guidewire to the lumen wall ascompared to the traditional guidewire or J-tip.

Variations of the device can include a compliant structure 104 with anexpanded diameter as small as that of a standard guidewire tip, e.g. inthe range of 0.010″ to 0.016″. Alternate variations can include acompliant structure 104 expanded diameter that is anywhere fromapproximately 1 mm to 4 mm, but could range from 0.5 mm up to 6 mm.

As noted above, the compliant tip structure 104 is collapsible for entryinto and deliverability through the microcatheter, and then canself-expand once unconstrained by the microcatheter or otherconstraining member.

The shape of the compliant structure 104 can comprise any shape thatpermits anchoring within a vessel. In some examples, the shape of thecompliant structure 104 is a spherical or ball shape. Alternatively, theshape can comprise an elongated shape, an egg shape, football shaped,elliptical, conical, cylindrical, or similar type of structure.

FIG. 2B illustrates a magnified view of a distal section of a guidewire100. As shown the guidewire comprises a compliant structure 104 at thedistal portion of a guidewire body where a portion of the elementsforming the compliant structure continuously extend along a section 106of the guidewire body. This integral extension of the compliantstructure can minimize or eliminate the number of joints or connectionsat the distal end of the guidewire. The presence of joints between theguidewire body and compliant structure can impede the ability of thedevice to assume a sufficiently reduced profile or can interfere withthe geometry/stiffness of the device causing problems when navigatingthe device through tortuous anatomy. Furthermore, joints can lead topotential failure locations, and may lead to fractured and loss ofcomponents within the body. Such joints may include welded, glued, orotherwise separately joined pieces into one or more points ofconnection.

FIGS. 3A and 3C illustrate a plurality of elements or struts 110 thatcan form the compliant structure. As shown, the elements or struts 110are continuous such that a distal portion can be fabricated to form theexpandable or anchoring portion 108 of the compliant structure 104. Theproximal section 106 of the compliant structure 104 remains continuous(and therefore integrally formed with the anchoring portion 108) and canbe affixed to the guidewire body 102 such that the proximal section 106of the compliant structure 104 extends along a portion of the guide wirebody 102. The proximal section 106 can comprise a proximal extension ofthe elements 110 that conforms closely to the guidewire body 102 anddoes not expand away from the body 102. In the area of the proximalsection 106, the guidewire body 102 can be of a somewhat smallerdiameter so that the combination of the body 102 and the elements 110 ofthe proximal section 106 is substantially similar in overall diameter tothe portion of the body 102 that is adjacent to and proximal of theproximal section 106. The elements 110 in the proximal section 106 canextend longitudinally and generally parallel to each other and to theguidewire body 102, or they can be braided together to form a tube thatclosely surrounds the body 102, or coiled or wound closely around thebody 102. In certain variations, elements or struts 110 run continuouslyto the center of the guide wire 102 construction from the anchoringportion 108 and then back again to the center of the guide wire 102 asillustrated in FIG. 3C.

In one variation, the elements or struts 110 comprise superelasticnitinol wire, with several wires woven or braided together and heat setto form the anchoring portion 108 as shown in FIG. 3C. In somevariations, the anchoring portion 108 can be heat set. The diameter ofthe elements can vary depending upon the desired properties of thecompliant structure 104. In one example, the elements or struts 110 cancomprise 0.001″ to 0.003″ diameter wire. The elements can be formed froma variety of materials, including but not limited to solid Nitinol wire,a shape memory alloy, a metal alloy or a hypotube filled with a platinumcore (e.g., a drawn filled tube). In certain variations the drawn filledtube (DFT) wire comprises platinum and Nitinol, e.g. 30% platinum and70% Nitinol. Decreasing the amount of platinum and increasing theNitinol increases the wire strength and results in higher columnstrength. In yet another example, the elements 110, can be processed toproduce the desired properties.

Additionally, the compliant structure can be formed with a mixture ofwires of different materials, such as Nitinol and platinum wires, orwires of different size or cross-sectional geometry (i.e. flat wire,square wire, or ribbon wire, etc.)

The remaining construction of attaching the compliant structure to theguidewire assembly is readily apparent to anyone skilled in the art. Inone variation, the proximal end of the elements 110 could be coveredwith a standard stainless coil or similar structure. Alternatively, orin combination the proximal end of the elements 110 could be bonded(such as adhesive bonded) to a ground core wire. The joined assemblycould be covered with PTFE (common in the industry) or with ahydrophilic coating (also common in the industry). It could also be leftuncoated if desired.

In alternative variations, the compliant structure 104 can be formed asa separate or discrete structure, such as a separate or discrete braidor laser cut tube or sheet (see FIG. 3B), and attached to the distal endof the guidewire body 102. The attachment method could consist ofwelding, soldering, crimping, adhesive bonding, etc. However, in such acase, the guidewire body can be configured to transition between theguidewire body and the compliant structure. Such a transition willprevent a sharp bend from forming between the guidewire body 102 and theanchor portion 108 (or the compliant portion 104).

FIGS. 4A and 4B show cross sectional view of an example of a variationof an element or strut 110 (for use in the compliant structure 104)comprising a wire. As shown, the wire can take any of a number ofconfigurations depending on the particular application. For example,individual wires (forming the elements or struts) can themselvescomprise a bundle of smaller wires or filaments. In addition, the wirescan be selected from materials such as stainless steel, titanium,platinum, gold, iridium, tantalum, Nitinol, alloys, and/or polymericstrands. In addition, the wires used in constructing the compliantstructure 104 may form a heterogeneous structure having combinations ofwires of different materials to produce a guidewire or compliantstructure having the particular desired properties. For example, one ormore wires of the compliant structure 104 or the body 102 may comprise ashape memory or superelastic alloy to impart predetermined shapes orresiliency to the device. In some variations, the mechanical propertiesof select wires can be altered. In such a case, the select wires can betreated to alter properties including: brittleness, ductility,elasticity, hardness, malleability, plasticity, strength, and toughness.

The compliant structure 104 or the guidewire body 102 may include anumber of radiopaque wires, such as gold or platinum wires for improvedvisibility under fluoroscopic imaging. In other words, any combinationof materials may be incorporated into the device. In addition to thematerial choice, the size of the wires may vary as needed. For example,the diameters of the wires may be uniform or may vary as needed.

In addition, the individual wires may have cross-sectional shapesranging from circular, oval, D-shaped, rectangular, etc. FIG. 4Aillustrates one possible variation in which a number of smaller-diameterwires 120 are positioned around a central larger-diameter wire 122.Moreover, the compliant structure 104 is not limited to having wireshaving a uniform cross-sectional shape or size. Instead, the device canhave wires having non-uniform cross-sectional shapes. For example, anyone or more of the wires 120, 122 can have a different cross-sectionalshape or size than a remainder of the wires. Clearly, any number ofvariations is within the scope of this disclosure.

In another variation depicted in FIG. 4B, one or more of the struts orelements used in the compliant structure 104 or the body 102 cancomprise a Drawn Filled Tube (DFT) such as those provided by Fort WayneMetals, Fort Wayne, Ind. As shown in FIG. 4B, such a DFT wire 130 cancomprise a first material or shell 132 over a core of a second material134 having properties different from those of the shell. While a varietyof materials can be used, one useful variation includes a DFT wirehaving a superelastic (e.g., Nitinol) shell with a radiopaque materialcore within the superelastic shell. For example, the radiopaque materialcan include any commercially used radiopaque material, including but notlimited to platinum, iridium, gold, tantalum, or similar alloy. Onebenefit of making a compliant structure from DFT material is that ratherthan employing one or more discrete radiopaque wires or elements in thecompliant structure, the entire compliant structure can be fabricatedfrom a superelastic material while, at the same time, the superelasticcompliant structure is radiopaque due to the core of radiopaque materialwithin the superelastic shell. Any suitable composite DFT material canbe employed in some or all of the elements 110 of the compliantstructure 104.

As noted above, the construction of the compliant structure can includesingle wires or additional wires, having properties or joined (e.g.braided, woven or coiled) in a variety of patterns to obtain desiredmechanical properties based on the intended application of the device.For example, in many variations, the wires, as shown in FIG. 3C can takea braided mesh shape, where the interlacing of the individual elementshelps generate the desired radial force. This radial force can bemodified by altering the pattern of the elements or wires and/orincreasing or decreasing the number or density of crossings that thewires make. The radial force can also be modified by altering the sizeof the wires, the specific alloy of wire used, and the processingmethods. However, the anchor portion of the compliant structure, or theentire compliant structure can be configured to be axially compressibleso as to absorb axial compression (e.g., the compliant structure readilycompresses or behaves similar to a spring when an axial force of thesort typically encountered in the advancement of endovascular devices isapplied at the distal tip). This feature allows the compliant structureto maximize the atraumatic interaction if it were to be inadvertentlyadvanced into the vessel wall. As noted above, the portion of theguidewire adjacent to the anchor portion should also be configured toprevent sharp bends occurring between the anchor portion and guidewirebody. In any case, the construction and orientation of the elementsand/or struts forming the compliant structure can be chosen to obtainthe desired properties of outward radial force (for anchoring andstability within the vessel) and axial compliance (for minimum traumaticinteraction with the vessel wall).

FIG. 5A illustrates one example of method of using a guidewire 100deployed through a microcatheter 12 where the anchoring portion of thecompliant member 104 provides an atraumatic tip to the guidewire 100. Asillustrated, the compliant member 104 comprises a plurality of elementsin that can move relative to each other causing the frame member to becompliant while provide a uniform radial force in an outwardcircumferential direction from the guidewire body. This radial forcereduces trauma to the vessel regardless of the direction in which thecompliant member 104 engages the vessel 10. Therefore, the catheter 12can be withdrawn or re-inserted over the guidewire 100 (or inserted overthe guidewire 100 if the guidewire 100 is present before catheterinsertion), and optionally a second catheter or other over-the-wiredevice can be inserted over the guidewire 100 with a minimum of traumato the vessel wall.

In the variation shown in FIG. SA, the compliant member 104 is sizedsuch that the anchoring portion does not engage the wall of the vesselbut simply serves to prevent the end of the guidewire 100 from causingtrauma as the catheter 12 is removed and exchanged with a secondcatheter (not illustrated).

FIG. 5B illustrates another example of a method of using a guidewire 100where an anchoring portion 108 is sized to have a larger profile thanthe intended vessel. For example, a physician can select an anchoringportion with an expanded profile of 3 mm OD and place the guidewire intoa vessel of a smaller diameter (e.g., 2.5 mm). The configuration of thestruts or elements in the anchoring portion 108 exerts a radial forceagainst the vessel wall. As noted above, the radial force can be applieduniformly about a perimeter of the anchoring portion 108. Theapplication of force about the circumference of the vessel distributesforce to lessen trauma as well as anchor the guidewire to facilitateimproved catheter exchange. The relative sizing of the anchoring portion108 to the vessel immobilizes the tip of the guidewire 108 duringremoval of the catheter 12 and further reduces the ability of the tip toengage in undesired motion during the exchange where a second catheteris advanced over the guidewire 100, which remains in place. Therefore,the catheter 12 can be withdrawn or re-inserted over the guidewire 100(or inserted over the guidewire 100 if the guidewire 100 is presentbefore catheter insertion), and optionally a second catheter or otherover-the-wire device can be inserted over the guidewire I 00 with aminimum of trauma to the vessel wall.

The anchoring effect of the anchoring portion can serve to not onlyminimize undesired motion of the guidewire tip, but it may alsofacilitate the advancement of a second catheter (e.g. a secondmicrocatheter) or other device, especially if the second catheter (orsimilar device) is relatively large or bulky. The anchoring of the tipof the wire gives more stability for the entire guidewire assembly,which then provides more support for the navigation of the newmicrocatheter.

It should be noted that the amount of “anchoring” that the compliantmember delivers can be adjusted by varying the construction of thecompliant member. For example, the OD of the anchoring portion, the ODof the struts, elements, and/or wires used in fabricating the device,the number of wires used, the pattern/density of the wires creating thestructure, the number of crossings, and to a lesser extent, variationsin the nitinol alloy and processing parameters can all be adjusted toprovide a guidewire device for use in specific parts of the anatomy.

The diameter or expanded profile size of various anchoring portions canrange from 1 mm to 4 mm, and/or otherwise as stated above. However,variations of the device can include sizes outside of this stated range.In addition, the length of the anchoring portion can range from between2 mm up to 10 mm or even longer. Furthermore the shape of the anchoringportion in the expanded configuration can vary. As shown above and inFIG. 6A, the anchoring portion can comprise a spherical profile 142. Insuch a case, the diameter of the anchoring portion is generally uniform.FIG. 6B illustrates an elliptical, or football shaped profile 144 wherethe maximum diameter is located towards a center of the anchoringportion (as measured along an axis of the guide body of the guidewire.FIG. 6C illustrates a variation of an egg-shaped 145 anchoring portionwhere the maximum diameter is offset towards either a proximal or distalend of the anchoring portion. FIG. 6D illustrates a conical or nearconical 146 profile. FIG. 6E illustrates a cylindrical profile 148,where the cylindrical profile 148 can include either an open or closedface at a distal end of the anchoring portion.

It should also be noted that although this disclosure is aimed at anexchange length guidewire, this atraumatic tip structure could bemanufactured in a shorter (i.e. standard) guide wire length. In thiscase, the physician would remove the original procedural guidewire andreplace it with any of the variants of the expandable-tipped orball-tipped guidewire disclosed here. This could be desired if thephysician does not plan to replace or exchange a microcatheter butnonetheless prefers a wire that is more atraumatic and/or offersanchoring for enhanced navigation or manipulation of the catheter.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Combination of the aspects of the variations discussed above as wellcombinations of the variations themselves are intended to be within thescope of this disclosure.

Various changes may be made to the invention described and equivalents(whether recited herein or not included for the sake of some brevity)may be substituted without departing from the true spirit and scope ofthe invention. Also, any optional feature of the inventive variationsmay be set forth and claimed independently, or in combination with anyone or more of the features described herein. Accordingly, the inventioncontemplates combinations of various aspects of the embodiments orcombinations of the embodiments themselves, where possible. Reference toa singular item, includes the possibility that there are plural of thesame items present. More specifically, as used herein and in theappended claims, the singular forms “a,” “and,” “said,” and “the”include plural references unless the context clearly dictates otherwise.

What is claimed is:
 1. A guidewire for advancing through a body lumen ina tortuous anatomy, the guidewire comprising: a guidewire body extendingbetween a proximal portion and a distal portion, the guidewire bodycomprising an elongated shape and configured to navigate the tortuousanatomy; a plurality of elements arranged to form a frame member havinga diameter greater than a cross sectional diameter of the distal portionof the guidewire body; where the plurality of elements in the framemember can move relative to each other causing the frame member to becompliant and provide a radial force in an outward circumferentialdirection from the guidewire body when released from a constrainingforce; and the plurality of elements converging from a proximal regionof the frame member to extend proximally from the frame member along thedistal portion of the guidewire body, thereby forming a proximalextension of the plurality of elements, where the plurality of elementsare continuous from the frame member into the proximal extension alongthe distal portion of the guidewire body.
 2. The guidewire of claim 1,wherein the guidewire body comprises a core member and where theplurality of elements are affixed to the core member along the proximalextension of the plurality of elements.
 3. The guidewire of claim 2,wherein the plurality of elements, in the proximal extension, are notradially expandable away from the core member.
 4. The guidewire of claim1, wherein the frame member comprises a shape selected from the groupconsisting of spherical, egg-shaped, football-shaped, elliptical,conical, cylindrical.
 5. The guidewire of claim 1, wherein the pluralityof elements comprises at least a first strut and a second strut, andwherein a cross sectional area of the first strut is different than across sectional area of the second strut.
 6. The guidewire of claim 1,wherein the plurality of elements forming the frame member areinterwoven to form the frame member.
 7. The guidewire of claim 1,wherein the plurality of elements forming the frame member are braidedto form the frame member.
 8. The guidewire of claim 1, wherein the framemember is permeable to allow fluid flow therethrough.
 9. The guidewireof claim 1, where at least one of the plurality of elements forming theframe member comprises a material selected from the group consisting ofa drawn filled tube, a nitinol wire, a shape memory alloy, asuper-elastic alloy, a stainless steel material, and a platinummaterial.
 10. The guidewire of claim 1, wherein the plurality ofelements, in the proximal extension, are bonded to the guidewire body.11. The guidewire of claim 1, wherein the plurality of elements in theproximal extension increase a column strength of distal portion of theguidewire body.
 12. The guidewire of claim 1, wherein the guidewire bodycomprises a core member and wherein the plurality of elements, in theproximal extension, are affixed against the core member along the distalportion of the guidewire body.
 13. A guidewire for advancing through abody lumen in a tortuous anatomy, the guidewire comprising: an elongatedmember extending between a proximal portion and a distal portion, theelongated member configured to navigate the tortuous anatomy; and adistal structure disposed at the distal portion of the guidewire body,the distal structure having: (a) a proximal region extending along thedistal portion of the elongated member, and (b) an expandable memberextending distally from the proximal region and configured to expandinto contact with a wall of the body lumen, wherein the distal structureis formed of a plurality of woven filaments, each of the filamentsextending between corresponding first and second ends, wherein the firstand second ends of each of the respective filaments are located at theproximal region of the distal structure.
 14. The guidewire of claim 13,wherein the elongated member comprises a solid core member.
 15. Theguidewire of claim 13, wherein the elongated member includes a lumen.16. The guidewire of claim 13, wherein one or more of the filamentscomprise a wire formed of a first material over a core of a secondmaterial, the second material being radiopaque.
 17. The guidewire ofclaim 13, wherein the distal structure further includes a coating. 18.The guidewire of claim 13, wherein the elongated member includes a coil,and wherein at least a portion of the proximal region of the distalstructure is surrounded by the coil.
 19. The guidewire of claim 13,wherein the plurality of filaments diverge from the distal portion ofthe elongated member to form the distal structure.
 20. The guidewire ofclaim 13, wherein the first and second ends of each of the plurality offilaments is affixed to a core wire.